This invention relates to ion generators or air ionizers being widely advertised and sold for use in homes and offices. These devices generate negative ions which have the effect of cleansing the air of many particles and creating a more invigorating atmosphere for humans. Enclosed spaces, with or without air conditioning tend to develop a surplus of positive ions, leading to lassitude, irritability and fatigue in persons therein, as well as a surfeit of smoke, haze, and pollution. High mountain air, notably clean and fresh, tends to have a high concentration level of negative ions.
These devices, many of which are small and portable, operate essentially by generating a high potential (on the order of 3,000 volts or more) which is then applied to one or more emitting elements, each of which may be a single needle or point, or a ball of "fuzz" providing many filament ends or some other type of conducting element affording surface discontinuities which will make possible a discharge or corona effect, releasing electrons or negative ions.
Predominantly these small "air energizers", "ionized oxygen generators" or "air ionizers" which are among the advertised designations, produce electrons by corona discharge, the electrons then combining with oxygen or other molecules in the air to produce ions. In U.S. Pat. No. 4,139,879 (1979) to LAWS, a sharp needle type emitter is said to produce a stream of electrically charged air molecules, or ions, propelled into the surrounding air by what is referred to as "the well known `electric wind` effect". The subject of the patent is not the discharge itself, but the use of a reflector to divert the ion stream while shielding the needle emitter.
Generally those ionizers in wide use tend to produce ionized oxygen, or ozone, predominantly. Since too high a concentration of ozone can have deleterious effects, U.S. Pat. No. 3,873,835 (1975) to IGNATJEV uses carbon emitters to generate CO.sub.3 - ions which, it is stated therein, are the dominant ions in air at [normal] atmospheric pressure for negative corona. In that invention, these emitter surfaces (either sharp points or a braided surface) are mounted on a powered fan which serves to provide a generated air flow to propagate and disperse the ion flow.
In 1920 U.S. Pat. No. 1,356,484 issued to BOLTAS for a motor driven rotating discharge wheel of pointed rod emitters, mounted on a tower, suitably charged, for the purpose as described of discharging current into the air (using the earth as a ground plane) for the purpose of making rain.